1. Field of the Disclosure
The present disclosure is directed to tolerance rings, particularly to tolerance rings for compressor motors, such as heating, ventilation, air-conditioning (HVAC) compressor motors.
2. Description of the Related Art
The present disclosure relates to tolerance ring assemblies, wherein a tolerance ring provides an interference fit between parts of an assembly, in which a first part has a cylindrical portion located in a cylindrical bore of a second part. In particular, the present disclosure relates to assemblies having a tolerance ring that provides an interference fit between a cylindrical component such as a flywheel or a bearing and a housing for the flywheel.
Improved engineering techniques have resulted in the need for greater accuracy of machine parts, raising manufacturing costs. Very close tolerances are required where press fits, splines, pins or keyways are employed to transmit torque in applications such as pulleys, flywheels, rotors, or drive shafts, or to prevent relative motions between parts, such as stators, main frames, lower frames, and compressor housings.
Tolerance rings may be used to provide an interference fit between parts required to transmit torque. Tolerance rings provide an efficient means of providing an interference fit between parts that may not be machined to exact dimensions. Tolerance rings have a number of other potential advantages, such as compensating for different linear coefficients of expansion between the parts, allowing rapid apparatus assembly, and durability.
A tolerance ring generally comprises a strip of resilient material, for example a metal such as spring steel, the ends of which are brought together to form a ring. A band of protrusions extend radially outwards from the ring, or radially inwards towards the center of the ring. Usually, the protrusions are formations, possibly regular formations, such as corrugations, ridges or waves.
When the ring is located in the annular space between, for example, a shaft and a bore in a housing in which the shaft is located, the protrusions are compressed. Each protrusion acts as a spring and exerts a radial force against the shaft and the surface of the bore, providing an interference fit between the shaft and the housing. Rotation of the housing or the shaft will produce similar rotation in the other of the shaft or the housing, as torque is transmitted by the tolerance ring. Typically, the band of protrusions is axially flanked by annular regions of the ring that have no formations (known in the art as “unformed regions” of the tolerance ring).
Although tolerance rings usually comprise a strip of resilient material that is curved to allow the easy formation of a ring by overlapping the ends of the strip, a tolerance ring may also be manufactured as an annular band. The term “tolerance ring” as used hereafter includes both types of tolerance ring. The term “shaft” as used hereafter includes any assembly component with a cylindrical portion, such as a shaft, flywheel, stator, rotor, main frame, lower frame, or a bearing.
Accordingly, the industry continues to need improvements in tolerance rings, particularly tolerance rings installed within compressor motors.
The use of the same reference symbols in different drawings indicates similar or identical items.